(photo source gizmodo)
According to a new French blog, the nexus-phone.com, which is publishing something like the futur terms of sale of nexus one, Google Checkout seems to be mandatory to buy it : "To place an order for the Device, you must register for a free Google Checkout account ...". http://www.nexus-phone.com/wp-content/uploads/2009/12/Passion_Terms_of_Sale.pdf
More information in French on nexus one http://www.nexus-phone.com/nexus-one/rumeur/le-prix-presume-du-nexus-one-530-544#more-544